US8804686B2 - Signaling of precoder related information in a MIMO system - Google Patents

Signaling of precoder related information in a MIMO system Download PDF

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US8804686B2
US8804686B2 US13/020,853 US201113020853A US8804686B2 US 8804686 B2 US8804686 B2 US 8804686B2 US 201113020853 A US201113020853 A US 201113020853A US 8804686 B2 US8804686 B2 US 8804686B2
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patterns
pattern
orthogonal cover
transmission
cyclic shift
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US20110200135A1 (en
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Stefano Sorrentino
George Jöngren
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Telefonaktiebolaget LM Ericsson AB
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/063—Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0667—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
    • H04B7/0669—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal using different channel coding between antennas
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0667—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
    • H04B7/0671—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal using different delays between antennas
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver

Definitions

  • the present invention relates generally to the control of devices in wireless communication networks, and more particularly relates to techniques for allocating reference signals to spatially multiplexed data transmissions.
  • Multi-antenna techniques can significantly increase the data rates and reliability of a wireless communication system.
  • throughput and reliability can be drastically improved if both the transmitter and the receiver are equipped with multiple antennas.
  • This arrangement results in a so-called multiple-input multiple-output (MIMO) communication channel; such systems and related techniques are commonly referred to as MIMO systems and MIMO techniques.
  • MIMO multiple-input multiple-output
  • LTE-Advanced The LTE-Advanced standard is currently under development by the 3 rd -Generation Partnership Project (3GPP).
  • 3GPP 3 rd -Generation Partnership Project
  • a core component in LTE-Advanced is the support of MIMO antenna deployments and MIMO related techniques for both downlink (base station to mobile station) and uplink (mobile station to base station) communications. More particularly, a spatial multiplexing mode (single-user MIMO, or “SU-MIMO”) for uplink communications is being designed.
  • SU-MIMO single-user MIMO is intended to provide mobile stations (user equipment, or “UEs” in 3GPP terminology) with very high uplink data rates in favorable channel conditions.
  • SU-MIMO consists of the simultaneous transmission of multiple spatially multiplexed data streams within the same bandwidth, where each data stream is usually referred to as a “layer.”
  • Multi-antenna techniques such as linear precoding are employed at the UE's transmitter in order to differentiate the layers in the spatial domain and to allow the recovery of the transmitted data at the receiver of the base station (known as eNodeB, or enB, in 3GPP terminology).
  • MU-MIMO Another MIMO technique supported by LTE-Advanced is MU-MIMO, where multiple UEs belonging to the same cell are completely or partly co-scheduled in the same bandwidth and during the same time slots.
  • Each UE in a MU-MIMO configuration may transmit multiple layers, thus operating in SU-MIMO mode.
  • each UE needs to transmit a unique reference signal (RS) at least for each transmitted layer.
  • RS unique reference signal
  • the receiver which is aware of which reference signal is associated to each layer, performs estimation of the associated channel by performing a channel estimation algorithm using the reference signal.
  • the estimated channel is an “effective” channel because it reflects the mapping of the spatially multiplexed layer to multiple antennas.
  • the estimate of the effective channel response is then employed by the receiver in the detection process.
  • Methods and apparatus are disclosed for assigning reference signals to transmission layers in a wireless network that supports single-user and/or multi-user MIMO.
  • techniques are disclosed for efficiently signaling the selection of a pattern of cyclic shifts and orthogonal cover codes to a mobile station, for use by the mobile station in subsequent multi-layer transmissions.
  • CS cyclic shift
  • OCC orthogonal cover code
  • a given value for the signaled bits always maps into a single table or other data structure that correlates the signaled values with patterns of CS/OCC assignments to transmission layers.
  • several tables or other data structures may exist, in which case the mapping of signaled values to CS/OCC assignment patterns may vary depending on additional factors, such as transmission rank, number of transmit antennas used by the UE, the selected codebook, the transmission modality (e.g., Open Loop, Closed Loop, Transmit Diversity).
  • the eNB is configured to use the three bits defined in previous releases of the LTE standards for reference signal assignments, to provide an indication of one of eight different index positions into any of the stored tables (where a different table may be defined for each combination of rank and the number of transmit antennas).
  • the eNB is further configured to “borrow” one or more unused bits from other defined signaling, to therefore extend the number of bits available for indicating index position. Doing so allows larger tables to be defined, with correspondingly larger numbers of reference signal patterns to choose from, and a correspondingly increased flexibility.
  • Complementary methods implemented at a mobile station include maintaining one or more defined tables representing a number of reference signal patterns for use by the UE, for sending demodulation reference signals on the uplink. These methods further include receiving signaling from the supporting wireless communication network, e.g., from a serving eNB, where the received signaling indicates an index value into the table (or tables), to be used by the UE for identifying the reference signal pattern to be used. Still further, the methods include the mobile station using the received index information to access the appropriate table and identify the reference signal pattern to be used, and to send demodulation reference signals according to that pattern.
  • a signal including a pattern index of B bits for identifying at least one reference signal for use by the wireless device in transmissions is received, wherein each of a plurality of available reference signals is defined by a cyclic shift and an orthogonal cover code.
  • the pattern index is then used to identify the cyclic shift and orthogonal cover code to be used in transmitting each of one or more spatially multiplexed data streams, according to one or more pre-determined tables that map each value of the pattern index to a pattern of cyclic shift and orthogonal cover code combinations for a first multi-layer transmission scenario, such that the patterns define a mapping of orthogonal cover codes and cyclic shifts to transmission layers as a function of the pattern index and where the patterns for the first multi-layer transmission scenario include a first pattern based on a set of cyclic shifts and a second pattern based on the same set of cyclic shifts, wherein each cyclic shift in the set is associated with a corresponding orthogonal cover code in the first pattern and wherein some, but not all, of the cyclic shifts in the set are associated with the same corresponding orthogonal cover codes in the second pattern.
  • the orthogonal cover codes are the same for each transmission layer in the first pattern but vary across the transmission layers in the second pattern. In either event, each of one or more spatially multiplexed data streams is transmitted using a corresponding reference signal for each data stream.
  • a first group of B bits to identify the cyclic shift and orthogonal cover code to be used by the second wireless node in transmitting each of one or more spatially multiplexed data streams is selected, according to one or more pre-determined tables that map each value of the first group of B bits to a pattern of cyclic shift and orthogonal cover code combinations for a first multi-layer transmission scenario, such that the patterns define a mapping of orthogonal cover codes and cyclic shifts to transmission layers as a function of the pattern index.
  • the patterns for the first multi-layer transmission scenario include a first pattern based on a set of cyclic shifts and a second pattern based on the same set of cyclic shifts, wherein each cyclic shift in the set is associated with a corresponding orthogonal cover code in the first pattern and wherein some, but not all, of the cyclic shifts in the set are associated with the same corresponding orthogonal cover codes in the second pattern.
  • the orthogonal cover codes are the same for each transmission layer in the first pattern but vary across the transmission layers in the second pattern. In either case, a signal including the first group of B bits is then transmitted, for use by the second wireless node in subsequent transmissions.
  • Mobile station and base station apparatus corresponding generally to the methods summarized above are also disclosed, and include processing circuits configured to carry out one or more of the techniques described herein for signaling and processing reference signal identification information.
  • processing circuits configured to carry out one or more of the techniques described herein for signaling and processing reference signal identification information.
  • FIG. 1 illustrates a wireless communication system in accordance with some embodiments of the present invention.
  • FIG. 2 is a block diagram illustrating components of a wireless node, such as a mobile station or a base station.
  • FIG. 3 illustrates an example mapping of cyclic shift indicator values to cyclic shift and orthogonal cover code patterns.
  • FIG. 4 illustrates additional example mappings of cyclic shift indicator values to cyclic shift and orthogonal cover code patterns.
  • FIG. 5 illustrates another example of mappings of cyclic shift indicator values to cyclic shift and orthogonal cover code patterns.
  • FIG. 6 is a process flow diagram illustrating a method for transmitting reference signals with one or more data streams.
  • FIG. 7 is another process flow diagram illustrating a method for signaling a wireless node of reference signals to be used by the wireless node in transmitting one or more data streams.
  • base station and UE should be considered non-limiting as applied to the principles of the invention.
  • terminology such as base station and UE should be considered non-limiting as applied to the principles of the invention.
  • the described techniques may be applied to the downlink in other contexts.
  • the base station or eNB in the discussion that follows could be considered more generically as “device 1 ” and the mobile station or UE considered as “device 2 ,” with these two devices comprising communication nodes communicating with each other over a radio channel.
  • FIG. 1 illustrates components of a wireless network 100 , including base station 110 (labeled eNB, per 3GPP terminology) and mobile stations 120 (each labeled UE, again according to 3GPP terminology).
  • eNB 110 communicates with UEs 120 and 120 using one or more antennas 115 ; individual ones or groups of these antennas are used to serve pre-defined sectors and/or to support any of various multi-antenna transmission schemes, such as multiple-input multiple-output (MIMO) transmission schemes.
  • MIMO multiple-input multiple-output
  • each UE 120 communicates with eNB 110 using antennas 125 .
  • LTE-Advanced is expected to support UEs having up to four transmit antennas, and eNBs having as many as eight.
  • the pictured UEs 120 each having four antennas, can transmit up to four spatially multiplexed layers to the eNB 110 over radio channels RC 1 and RC 2 , depending on the channel conditions.
  • a radio access terminal which communicates wirelessly with fixed base stations in the wireless network, can also be called a system, subscriber unit, subscriber station, mobile station, mobile, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, user device, or user equipment (UE).
  • An access terminal can be a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, computing device, or other processing device connected to a wireless modem.
  • SIP Session Initiation Protocol
  • WLL wireless local loop
  • PDA personal digital assistant
  • Base station 110 communicates with access terminals and is referred to in various contexts as an access point, Node B, Evolved Node B (eNodeB or eNB) or some other terminology.
  • Node B Evolved Node B
  • eNodeB Evolved Node B
  • base station is used herein to refer to a collection of functional elements (one of which is a radio transceiver that communicates wirelessly with one or more mobile stations), which may or may not be implemented as a single physical unit.
  • FIG. 2 is a block diagram of a wireless transceiver apparatus, illustrating a few of the components relevant to the present techniques, as realized in either a mobile station or a base station. Accordingly, the apparatus pictured in FIG. 2 can correspond to either end of the communication link pictured in FIG. 1 , i.e., as either eNB 110 or UE 120 .
  • the pictured apparatus includes radio circuitry 210 and baseband & control processing circuit 220 .
  • Radio circuitry 210 includes receiver circuits and transmitter circuits that use known radio processing and signal processing components and techniques, typically according to a particular telecommunications standard such as the 3GPP standard for Wideband CDMA and multi-carrier HSPA. Because the various details and engineering tradeoffs associated with the design of such circuitry are well known and are unnecessary to a full understanding of the invention, additional details are not shown here.
  • Baseband & control processing circuit 220 includes one or more microprocessors or microcontrollers 230 , as well as other digital hardware 235 , which may include digital signal processors (DSPs), special-purpose digital logic, and the like. Either or both of microprocessor(s) 230 and digital hardware may be configured to execute program code 242 stored in memory 240 , along with radio parameters 244 .
  • DSPs digital signal processors
  • radio parameters 244 may be configured to execute program code 242 stored in memory 240 , along with radio parameters 244 .
  • the program code 242 stored in memory circuit 240 which may comprise one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc., includes program instructions for executing one or more telecommunications and/or data communications protocols, as well as instructions for carrying out one or more of the techniques described herein, in several embodiments.
  • radio parameters 244 may include one or more pre-determined tables or other data relating cyclic shifts and orthogonal cover codes to transmission layers for multi-antenna transmission, so that the reference signals can be efficiently mapped to the layers with minimal signaling overhead required to communicate the mapping.
  • each reference signal is uniquely defined by a cyclic shift value (CS) and orthogonal cover code (OCC) applied to a pre-determined sequence. Twelve CS values and 2 OCC values are defined.
  • CS cyclic shift value
  • OCC orthogonal cover code
  • a straightforward signaling protocol is to signal each UE of the CS/OCC parameters for each layer in the downlink control information, as part of the Packet Data Control Channel (PDCCH).
  • PDCCH Packet Data Control Channel
  • An efficient assignment seeks maximum separation of CS and OCC combinations among the scheduled layers, in order to achieve better performance in channel estimation and to reduce inter-layer interference. Therefore, an efficient signaling protocol achieves a convenient trade-off between low signaling overhead and flexibility in the assignment of the reference signals, to allow high performance and efficient use of the uplink resources.
  • One proposed approach for signaling the UE of the CS/OCC combinations to apply to each layer in a multi-layer uplink transmission is to employ 3 bits from PDCCH for signaling the CS for a reference layer, e.g., “layer 0”, for a given UE.
  • the signaled CS in this case belongs to a predefined subset of the available CS's. If multiple layers are transmitted by the selected UE, the CS for each remaining layer is automatically defined by calculating a predefined offset from the CS used for the zero-th layer.
  • each CS position corresponds to a default OCC value—thus the OCC is automatically defined for each layer without any need for further signaling.
  • the number of multiplexed reference signals corresponds to the number of physical (or virtualized) antennas. The same approach to signaling the reference signals can be used in this case.
  • an additional signaling bit is used to invert the selection of the default OCC associated with each CS, for a given UE.
  • this feature implies an additional bit in the DL signaling overhead.
  • a related approach is to invert the value of the default OCC value per CS according to semi-static signaling from a higher layer. While this option would not result in additional signaling overhead at the link level, it still requires that more bits are used in the signaling.
  • each additional bit on PDCCH increases the overhead and reduces the coverage of control channels, thus adding bits to PDCCH signaling to add flexibility in OCC usage is undesirable.
  • semi-static signaling from higher layers is not fast enough to track fast and flexible scheduling at the link layer.
  • one or more tables that are based on a joint mapping of OCC and CS are used to advantageously define reference signal patterns, for use in assigning reference signal patterns to UEs for subsequent use in uplink transmissions.
  • a reference signal pattern table is defined for each combination of rank and number of transmit antennas.
  • N log 2(N) bits in the uplink grant
  • each of the N entries corresponds to a unique predefined joint mapping of OCC and CS values per layer.
  • a given value for the signaled bits always maps into a single table or other data structure that correlates the signaled values with patterns of CS/OCC assignments to transmission layers.
  • mapping of signaled values to CSS/OCC assignment patterns may vary depending on additional factors, such as transmission rank, number of transmit antennas used by the UE, the selected codebook, the transmission modality (e.g., Open Loop, Closed Loop, Transmit Diversity).
  • FIG. 3 An example of a set of tables that might be used by a UE having two antennas is given in FIG. 3 .
  • Two tables are provided—the first is used for one-layer transmission, while the second applies to two-layer transmission.
  • the rows in each table correspond to the two available OCC's ( ⁇ +1, +1 ⁇ , ⁇ +1, ⁇ 1 ⁇ ), while each column corresponds to one of the twelve available CS's.
  • the entries in each table, 0 to 7, correspond to the patterns identified by the three signaling bits sent from the eNB.
  • a UE that receives three bits indicating pattern 5 will use a CS of 7 along with an OCC of ⁇ +1, +1 ⁇ . If that UE instead receives three bits indicating pattern 2, then it will use a CS of 3 along with an OCC of ⁇ +1, ⁇ 1 ⁇ . If the UE is transmitting two layers, however, it uses the rank 2 table. In this case, if the UE is assigned to pattern 5, then it uses a CS of 1 for one layer and a CS of 7 for the second layer. The reference signal on both layers uses an OCC of ⁇ +1, ⁇ 1 ⁇ .
  • each of the eight reference signal patterns includes two entries, one for each transmission layer, and each pattern identifies two CS's, each of the two CS's in a pattern associated with a single OCC.
  • the performance is not affected by the order in which a set of CS/OCC combinations is assigned to layers, thus the actual numbering of the layers with the pattern is a matter of design choice.
  • the two CS's identified by a given signaling value can be assigned to layer 0 and layer 1 by working from the left to the right, or vice-versa, provided only that the UE and eNB share the same approach.
  • the tables provided in FIG. 3 are only an example—many other mappings of signaling values to various patterns of CS/OCC combinations are possible. It will also be appreciated that similar tables can be constructed to accommodate different numbers of OCC's and CS's, in systems that adopt a different reference signal scheme. Furthermore, as suggested above, the tables mapping signaling bits to CS/OCC patterns may also be made to depend on additional or alternative variables, such as transmission mode and/or the level of UE mobility. With this latter approach, the flexibility is further increased without requiring additional signaling.
  • a flexible signaling scheme should facilitate the efficient co-scheduling of several mobile terminals in MU-MIMO mode, where each mobile may be transmitting on one or several layers.
  • some embodiments provide that for each table of available CS/OCC patterns for rank greater than or equal to 2, one or more patterns having the same OCC value for all layers and one or more patterns having alternating OCC values between their layers are present.
  • pattern 1 identifies a CS value of 1 and an OCC of ⁇ +1, +1 ⁇ .
  • rank 1 table of FIG. 4 for 4-antenna UEs
  • pattern 1 identifies a CS value of 1 and an OCC of ⁇ +1, ⁇ 1 ⁇ .
  • the opposite OCC value is used by 2-antenna and 4-antenna UEs.
  • the rank 3 and rank 4 tables include patterns in which the OCC values are constant across all of the layers as well as patterns in which the OCC values vary. For instance, in the rank 4 table, patterns 0, 1, 2, 6, and 7 each assign varying OCC's to the four transmission layers. Patterns 3, 4, and 5, on the other hand, use the same OCC for all four transmission layers. This approach allows improved scheduling flexibility and performance in MU-MIMO scenarios.
  • Tables 1 and 2 which list CS/OCC assignments from FIG. 4 for four-antenna UEs, for rank-4 transmissions.
  • Table 1 lists the assignments for pattern 6, while Table 2 shows the corresponding assignments for pattern 3.
  • a “pattern” refers to a set of CS/OCC-to-layer assignments corresponding to a given signaling value
  • a “pattern” refers to a set of CS/OCC-to-layer assignments corresponding to a given signaling value
  • the eNB (or other supporting network node) and the UE (or other item of user equipment) are each configured with one or more tables or equivalent data structures that are used for indicating and selecting the pattern(s) of demodulation reference signals to be used by the UE in subsequent uplink transmissions.
  • the eNB signals to each UE the pattern that should be used by that UE by simply indicating the table index value.
  • the UE which is configured with a table or equivalent data structure that matches the one used by the eNB, retrieves the pattern identified by the signal from the eNB, and uses the identified mapping to assign reference signals to transmission layers.
  • the three bits allocated for reference signal assignments in previous LTE releases can be used for this purpose, or other bits may be used, and, further, one or more additional, currently unused bits may be used for increasing the size of the reference signal pattern tables.
  • a table applicable to a given scenario is configured to include reference signal patterns using one OCC, and patterns that alternate between OCCs.
  • a pattern refers to a set of CS/OCC combinations mapped to the transmission layers.
  • Each signaling value e.g., 3-bit value, identifies one of those patterns.
  • a table includes eight patterns. This definition permits the eNB to choose reference signal patterns that fall within one OCC or span both OCCs, allowing extra flexibility in assigning reference signal patterns in cases where separation in the CS domain is sufficient, and in cases where separation in the CS domain is not sufficient.
  • the eNB has great flexibility in assigning the reference signal patterns that yield the best separation, given the particular scenario involved.
  • the eNB is configured to use the three bits defined in previous releases of the LTE standards for reference signal assignments, to provide an indication of one of eight different index positions into any of the stored tables (where a different table may be defined for each combination of rank and the number of transmit antennas).
  • the eNB is further configured to “borrow” one or more unused bits from other defined signaling, to therefore extend the number of bits available for indicating index position. Doing so allows larger tables to be defined, with correspondingly larger numbers of reference signal patterns to choose from, and a correspondingly increased flexibility.
  • rank-1 patterns for four-antenna UEs provided in FIG. 5 .
  • This table includes 16 patterns, of which only eight can be directly indexed using just the three bits transmitted on PDCCH.
  • the extra bit from the codebook index could be used as the most significant bit, to identify either patterns 0-7 or patterns 8-15, while the three bits from the PDCCH are used as the least significant bits, to identify the exact pattern.
  • this approach is not limited to the codebook field, but can be applied also to other partly unused signaling fields in the uplink grant, e.g., if the most dynamic flexibility is required, or even in less frequent signaling messages, e.g., if less dynamic flexibility is acceptable.
  • a different table may be used for different MIMO “modalities.”
  • the eNB may track or otherwise identify the appropriate table to use based on the modality, and determine the correct index value to use for each of one or more UEs.
  • the eNB jointly evaluates the set of UEs that are co-scheduled in a MU-MIMO context, and determines the combination of reference signal pattern assignments that yields the best separation between reference signals at the eNB.
  • each UE may store several different reference signal pattern tables, corresponding to those used by the eNB, for use in different operating scenarios, and the UE may be configured to select the appropriate table based on rank and number of antennas, and/or based on other variables. Further, for a given rank and number of antennas, there may be more than one defined table to pick from, selected, for example, based either on the evaluation of one or more variables, such as MIMO mode, UE mobility, etc.
  • the process flow diagram of FIG. 6 illustrates a generalized embodiment of several of the above techniques, as might be implemented in a wireless device that receives signaling indicating a reference signal pattern.
  • the illustrated method begins with receiving a signal that includes B bits for identifying at least one reference signal for use by the wireless device in transmissions, where each of a plurality of available reference signals is defined by a cyclic shift and an orthogonal cover code.
  • the method next includes using the B bits to identify the cyclic shift and orthogonal cover code to be used in transmitting a data stream or each of one or more spatially multiplexed data streams, according to one or more pre-determined tables that map each value of the B bits to a pattern of cyclic shift and orthogonal cover code combinations for at least one multi-layer or multi-antenna transmission scenario.
  • the patterns define a mapping of orthogonal cover codes and cyclic shifts to transmission layers as a function of the pattern index and, in some cases, as a function of the number of transmit antennas to be used in the transmission.
  • the patterns for a multi-layer transmission scenario include a first pattern based on a set of cyclic shifts and a second pattern based on the same set of cyclic shifts, wherein each cyclic shift in the set is associated with a corresponding orthogonal cover code in the first pattern and wherein some, but not all, of the cyclic shifts in the set are associated with the same corresponding orthogonal cover codes in the second pattern.
  • the patterns for the multi-layer transmission scenario include a first pattern in which the orthogonal cover codes are the same for each transmission layer and a second pattern in which the orthogonal codes vary across the transmission layers While several examples of these tables, e.g., for two-layer, three-layer, and four-layer transmission, were described above in connection with FIGS. 3-5 , the method of FIG. 6 is not limited to those exact tables nor is the method limited to four or fewer layers.
  • each of one or more spatially multiplexed data streams are transmitted using a corresponding reference signal for each data stream, wherein the corresponding reference signals are those identified with the B bits.
  • the pre-determined tables specify a first set of patterns for multi-layer transmission using two transmit antennas and a second set of patterns for multi-layer transmission using four transmit antennas, wherein the first and second set of patterns include at least one cyclic shift value that has different corresponding orthogonal cover codes for two-antenna and four-antenna transmission.
  • the patterns may map orthogonal cover codes and cyclic shifts to transmission layers as a function of the pattern index and as a function of the number of antennas to be used for transmitting the at least one data stream.
  • the multi-layer transmission scenario described above may be a three-layer transmission scenario.
  • the one or more tables further map each value of the pattern index to an additional pattern of cyclic shift and orthogonal cover code combinations for a four-layer transmission scenario, wherein the additional patterns define a mapping of orthogonal cover codes and cyclic shifts to transmission layers as a function of the pattern index and wherein the additional patterns for the four-layer transmission scenario include a third pattern in which the orthogonal cover codes are the same for each transmission layer and a fourth pattern in which the orthogonal codes vary across the transmission layers.
  • the third and fourth patterns each include at least one cyclic shift that is associated with a different orthogonal cover code in each of the third and fourth patterns, and wherein the third and fourth patterns each include at least one other cyclic shift that is associated with the same orthogonal cover code in each of the third and fourth patterns.
  • the one or more pre-determined tables may specify one or more patterns that are identified by one or more other parameters, in addition to the B bits, in which case the method pictured in FIG. 6 includes identifying the cyclic shift and orthogonal cover code to be used in transmitting each of one or more spatially multiplexed data streams based on the one or more other parameters.
  • These one or more other parameters comprise at least one of: a transmission rank, a number of transmit antennas available to the wireless device, a codebook selection, and a transmission modality type.
  • the process flow diagram of FIG. 7 illustrates an example method that is implemented at the other end of the wireless link from the device that carries out the method of FIG. 6 .
  • the device carrying out the method of FIG. 7 is likely to be the eNB.
  • This method begins with the selection of a first group of B bits to identify the cyclic shift and orthogonal cover code to be used by the second wireless node in transmitting each of one or more spatially multiplexed data streams, according to one or more pre-determined tables that map each value of the first group of B bits to a pattern of cyclic shift and orthogonal cover code combinations for one-layer and two-layer transmissions.
  • the first group of B bits are then transmitted to the second wireless node.
  • some embodiments of the method of FIG. 7 include an additional step in which a second group of B bits are selected, for a third wireless node, and transmitted to the third wireless node for its use in transmitting one or more spatially multiplexed layers to the first node.
  • this second group of B bits is selected according to the stored tables described above.
  • the selection of the second group of B bits is also based on the selection of reference signals for the second wireless node.
  • the selection of the second group of B bits is based on the first group of B bits.
  • the one or more pre-determined tables used in the method of FIG. 7 may specify a first set of patterns for multi-layer transmission using two transmit antennas and a second set of patterns for multi-layer transmission using four transmit antennas, in some embodiments, wherein the first and second set of patterns include at least one cyclic shift value that has different corresponding orthogonal cover codes for two-antenna and four-antenna transmission.
  • the one or more pre-determined tables specify a third set of patterns for three-layer transmissions and a fourth set of patterns for four-layer transmissions, at least one of the third and fourth sets of patterns including a first pattern in which the same orthogonal cover code is used for each layer and a second pattern in which different orthogonal cover codes are assigned to two or more of the layers.
  • At least one of the third and fourth sets of patterns in some of these embodiments includes a third pattern and a fourth pattern, wherein the third and fourth patterns each include at least one cyclic shift that is associated with a different orthogonal cover code in each of the third and fourth patterns, and each include at least one other cyclic shift that is associated with the same orthogonal cover code in each of the third and fourth patterns.
  • the one or more pre-determined tables in some embodiments may specify one or more patterns that are identified by one or more other parameters, in addition to the first group of B bits, and wherein the first group of B bits are selected based on the one or more other parameters.
  • processing circuits such as the baseband & control processing circuits 220 of FIG. 2 , are configured to carry out one or more of the methods describe above, including the methods pictured in FIGS. 6 and 7 .
  • these processing circuits are configured with appropriate program code, stored in one or more suitable memory devices, to implement one or more of the techniques described herein.
  • program code stored in one or more suitable memory devices

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130322229A1 (en) * 2010-05-03 2013-12-05 Pantech Co., Ltd. Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in mimo environment

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101764627B (zh) * 2008-12-26 2014-05-07 株式会社Ntt都科摩 确定上行链路的解调导频序列的方法、终端以及上行链路系统
CN102859893B (zh) * 2010-02-16 2016-06-08 瑞典爱立信有限公司 基于码和循环移位的mimo层特定参考信号
KR101828621B1 (ko) 2010-04-02 2018-03-22 인터디지탈 패튼 홀딩스, 인크 업링크 사운딩 기준 신호 구성 및 전송 방법
WO2011120233A1 (fr) * 2010-04-02 2011-10-06 富士通株式会社 Appareil et procédé de génération de code de couverture orthogonal (occ), et appareil et procédé de mappage d'occ
US8787304B2 (en) * 2010-06-22 2014-07-22 Acer Incorporated Method for reference signal pattern allocation and related communication device
CN102300313B (zh) * 2010-06-28 2013-03-27 华为技术有限公司 专用解调参考信号的资源配置方法和相关装置
US8625695B2 (en) * 2010-08-13 2014-01-07 Nec Laboratories America, Inc. Feed-forward control signaling and decoding schemes
WO2014075294A1 (fr) * 2012-11-16 2014-05-22 华为技术有限公司 Procédé de transmission de signal de référence (rs), équipement d'utilisateur et appareil de réseau
US9844046B2 (en) * 2013-04-01 2017-12-12 Panasonic Intellectual Property Corporation Of America Terminal, base station, method of generating DMRS, and transmission method
WO2014208953A1 (fr) 2013-06-25 2014-12-31 엘지전자 주식회사 Procédé et appareil pour estimer l'auto-interférence dans un système à accès sans fil supportant les radiocommunications en duplex intégral
CN104717753B (zh) * 2013-12-17 2019-09-13 北京三星通信技术研究有限公司 一种非正交通信方法、基站及终端
KR102287875B1 (ko) 2015-04-17 2021-08-09 삼성전자주식회사 무선 통신 시스템에서 기준 신호들을 송신하기 위한 장치 및 방법
CN108242985B (zh) * 2016-12-23 2022-04-12 维沃移动通信有限公司 一种参考信号配置方法、网络侧设备和用户设备

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070036066A1 (en) * 2005-08-15 2007-02-15 Motorola, Inc. Method and apparatus for pilot signal transmission
WO2010097121A1 (fr) * 2009-02-27 2010-09-02 Nokia Siemens Networks Oy Appareil et procédé destinés à la communication à entrées multiples sorties multiples d'un utilisateur unique au moyen de décalages circulaires
WO2010149206A1 (fr) * 2009-06-23 2010-12-29 Nokia Siemens Networks Oy Procédé, appareil et produit de programme d'ordinateur associé pour la configuration de canal d'information

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2056515B1 (fr) * 2007-10-30 2019-06-12 Cellular Communications Equipment Llc Procédés, appareils, système et produit de programme informatique correspondant pour l'affectation de ressources
KR101027233B1 (ko) 2008-07-23 2011-04-06 엘지전자 주식회사 다중 안테나 시스템에서 참조신호 전송 방법
WO2010147853A2 (fr) * 2009-06-16 2010-12-23 Interdigital Patent Holdings, Inc. Décalage cyclique adaptatif de rang pour signal de référence de démodulation
US9048976B2 (en) * 2009-06-22 2015-06-02 Lg Electronics Inc. Apparatus and method for transmitting reference signals in wireless communication system
CN101645868B (zh) 2009-08-31 2014-12-10 中兴通讯股份有限公司 一种参考信号的发送方法和装置
US8908617B2 (en) * 2009-12-31 2014-12-09 Samsung Electronics Co., Ltd. Uplink demodulation reference signal design for MIMO transmission
US9258160B2 (en) * 2010-01-11 2016-02-09 Qualcomm Incorporated Multiplexing demodulation reference signals in wireless communications
CN102859893B (zh) * 2010-02-16 2016-06-08 瑞典爱立信有限公司 基于码和循环移位的mimo层特定参考信号
KR101824902B1 (ko) * 2010-02-22 2018-02-02 삼성전자 주식회사 상향링크 레퍼런스 신호들을 위한 시퀀스 호핑 및 직교 커버링 코드의 적용
JP2012186736A (ja) * 2011-03-07 2012-09-27 Sharp Corp 端末装置、基地局装置、および無線通信システム

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070036066A1 (en) * 2005-08-15 2007-02-15 Motorola, Inc. Method and apparatus for pilot signal transmission
WO2010097121A1 (fr) * 2009-02-27 2010-09-02 Nokia Siemens Networks Oy Appareil et procédé destinés à la communication à entrées multiples sorties multiples d'un utilisateur unique au moyen de décalages circulaires
US20110299625A1 (en) * 2009-02-27 2011-12-08 Kari Juhani Hooli Apparatus and Method for Single User Multiple Input Multiple Output Communication Employing Cyclic Shifts
WO2010149206A1 (fr) * 2009-06-23 2010-12-29 Nokia Siemens Networks Oy Procédé, appareil et produit de programme d'ordinateur associé pour la configuration de canal d'information
US20120170683A1 (en) * 2009-06-23 2012-07-05 Frank Frederiksen Methods, Apparatuses, and Related Computer Program Product for Information Channel Configuration

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
3RD Generation Partnership Project. "Considerations on Uplink DM-RS sequence in LTE-Advanced." 3GPP TSG RAN WG1 Meeting #59-bis, R1-100668, Valencia, Spain, Jan. 18-22, 2010, pp. 1-6.
3rd Generation Partnership Project. "DM-RS in Support of UL Spatial Multiplexing." 3GPP TSG-RAN WG1 #59bis, R1-100691, Valencia, Spain, Jan. 18-22, 2010.
3rd Generation Partnership Project. "OCC and CS for UL RS in SU/MU-MIMO." 3GPP TSG RAN WG1 Meeting #59bis, R1-100378, Valencia, Spain, Jan. 18-22, 2010.
3rd Generation Partnership Project. "Uplink DM-RS Resource Configuration for LTE-Advanced." 3GPP TSG RAN WG1 Meeting #60, R1-101008, San Francisco, California, USA, Feb. 22-26, 2010.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130322229A1 (en) * 2010-05-03 2013-12-05 Pantech Co., Ltd. Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in mimo environment
US8964520B2 (en) * 2010-05-03 2015-02-24 Pantech Co., Ltd. Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in MIMO environment
US9264273B2 (en) 2010-05-03 2016-02-16 Pantech Co., Ltd. Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in mimo environment
US9531574B2 (en) 2010-05-03 2016-12-27 Pantech Inc. Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in MIMO environment
US9935804B2 (en) 2010-05-03 2018-04-03 Apple Inc. Apparatus and method for transmitting and receiving of cyclic shift parameter for supporting orthogonality in MIMO environment

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US9397806B2 (en) 2016-07-19
US20160211958A9 (en) 2016-07-21
EP2537261A1 (fr) 2012-12-26
ES2446378T3 (es) 2014-03-07
CN102859893A (zh) 2013-01-02
EP2537261B1 (fr) 2013-12-04
CN102859893B (zh) 2016-06-08
MX2012008900A (es) 2012-08-31
US10897335B2 (en) 2021-01-19
EP2685637A1 (fr) 2014-01-15
WO2011102782A1 (fr) 2011-08-25
US20110200135A1 (en) 2011-08-18
US20140301316A1 (en) 2014-10-09
CA2790121A1 (fr) 2011-08-25
US20160294524A1 (en) 2016-10-06

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